Six medicinal plants indigenous to Africa were evaluated for their activity on experimental thrombosis in mice. Of the plants screened, the extract of Commiphora molmol exhibited the strongest antithrombotic activity, while the extract of Ageratum conyzoides showed no marked activity. This study established the antithrombotic effect of the extracts of Azadiractha indica, Bridelia ferruginea, Commiphora molmol, Garcinia kola and Curcuma longa